|Publication number||US7400807 B2|
|Application number||US 11/556,658|
|Publication date||Jul 15, 2008|
|Filing date||Nov 3, 2006|
|Priority date||Nov 3, 2005|
|Also published as||US20070206912|
|Publication number||11556658, 556658, US 7400807 B2, US 7400807B2, US-B2-7400807, US7400807 B2, US7400807B2|
|Inventors||John D. Minelly, Matthias P. Savage-Leuchs, Barton J. Jenson, Jason D. Henrie, Eric C. Eisenberg|
|Original Assignee||Aculight Corporation|
|Export Citation||BiBTeX, EndNote, RefMan|
|Patent Citations (29), Non-Patent Citations (10), Referenced by (24), Classifications (30), Legal Events (4)|
|External Links: USPTO, USPTO Assignment, Espacenet|
This application claims benefit of U.S. Provisional Patent Application No. 60/733,977 filed on Nov. 3, 2005, titled “APPARATUS AND METHOD FOR A WAVEGUIDE WITH AN INDEX PROFILE MANIFESTING A CENTRAL DIP FOR BETTER ENERGY EXTRACTION,” which is incorporated herein by reference in its entirety.
The invention relates to fiber lasers and amplifiers, and more particularly to optical fiber gain media having a central dip or reduction in index of refraction and/or doping concentration of the active laser species such as erbium and./or ytterbium, in order to provide higher optical-power output.
Fiber lasers are typically lasers with optical fibers as gain media, although some lasers with a semiconductor gain medium and a fiber cavity have also been called fiber lasers. In most cases, the gain medium is a fiber doped with rare-earth ions such as erbium, neodymium, ytterbium, or thulium, and one or several laser diodes are used for pumping. Some benefits associated with fiber lasers include: a large gain bandwidth due to strongly broadened laser transitions in glasses, enabling wide wavelength tuning ranges and/or the generation of ultra-short pulses, the potential for very high output powers (e.g., several kilowatts with double-clad fibers) due to a high surface-to-volume ratio (avoiding excessive heating) and the guiding effect, which avoids thermo-optical problems even under conditions of significant heating just to name a few.
Additional benefits can accrue in fiber lasers that have a modified gain medium or, in the case of a fiber laser, a modified gain fiber. As disclosed above, fiber lasers often contain certain glasses such as silica or silica doped with germanium, or crystals such as Nd:YAG (i.e., neodymium-doped yttrium aluminum garnet), Yb:YAG (i.e., yttrium-doped YAG), Yb:glass, or Ti:sapphire, in the form of solid pieces or optical glass fibers. These fibers are doped with some active stimulated-emission ions (also called amplifying or laser ions), that in most cases are trivalent rare-earth ions, and which are optically pumped. The doping density of crystals and glasses often has to be carefully optimized. A high doping density may be desirable for good pump absorption in a short length, but may lead to energy losses related to quenching processes, (e.g. caused by clustering of laser-active ions and energy transport to defects).
In addition to doping the density of a gain fiber, additional energy can be generated by addressing issues related to the refractive index of the core and the cladding material. More to the point, the energy generated by a fiber laser is also dependent upon the various refractive and modal index values associated with a particular gain-fiber configuration. In some configurations, a gain fiber will be configured such that its refractive index is a step index value. The step index fiber is the simplest case of a standard gain fiber.
Despite the benefits associated with fiber lasers, there are problems associated with these types of lasers. For example, complicated temperature-dependent polarization evolution, the various nonlinear effects of which often limit the performance, and risk of fiber damage at high powers (commonly known as “fiber fuse”). When fiber fuse occurs, the fiber can burn down starting from the output end and propagating back towards the input end.
The problems of temperature-dependent polarization and fiber fuse become even more acute, given the current and proposed uses of fiber lasers. As described above, fiber lasers can be used to produce very high output powers. Given these high output powers, fiber lasers have uses for military and industrial applications requiring large amounts of energy. Accordingly, it is necessary to develop methods and apparatus to enable high energy to be used in conjunction with fiber lasers, while at the same time avoiding the aforementioned problems of, for example, fiber fuse.
In some embodiments, the present invention utilizes a gain medium in the form of a gain fiber that has a refractive index with a significant central dip. The benefits of this central dip are apparent when an input beam is akin to that of a Gaussian mode. In some embodiments, the core is of a relatively large diameter (e.g., 20 microns or more), and the mode (i.e., the primary mode) of the signal has a relatively large cross-sectional area (LMA or large mode area) in the large core. In some embodiments, a linear-polarization-02 (LP02) mode is used such that the primary mode fills the relatively large core and extracts as much energy as possible into the primary mode from the active species, thus leaving little energy left for possible amplification on other modes.
In some embodiments, the refractive index and the concentration of lasing species (e.g., erbium and ytterbium) both increase at the periphery of the core and dip in the center of the core. In some embodiments, an outer cladding of lower index of refraction is provided, in order that pump light introduced into the inner cladding is kept inside the outer cladding, but is allowed into the core in order to pump lasing and/or amplification of a signal wavelength.
Although the following detailed description contains many specifics for the purpose of illustration, a person of ordinary skill in the art will appreciate that many variations and alterations to the following details are within the scope of the invention. Accordingly, the following preferred embodiments of the invention is set forth without any loss of generality to, and without imposing limitations upon the claimed invention.
In the following detailed description of the preferred embodiments, reference is made to the accompanying drawings that form a part hereof, and in which are shown by way of illustration specific embodiments in which the invention may be practiced. It is understood that other embodiments may be utilized and structural changes may be made without departing from the scope of the present invention.
The leading digit(s) of reference numbers appearing in the Figures generally corresponds to the Figure number in which that component is first introduced, such that the same reference number is used throughout to refer to an identical component which appears in multiple Figures. Signals and connections may be referred to by the same reference number or label, and the actual meaning will be clear from its use in the context of the description.
As used herein, the term “waveguide” includes a signal-carrying core of an optical fiber as well as a waveguide formed in or on a slab or other substrate.
The inventors have observed that, in some embodiments, improved performance in a pulsed fiber laser can be obtained where the gain fiber contained a significant central dip in index of refraction; i.e., when the core has a central area of lower index of refraction as compared to the outer portions of the core. When seeded with a “Gaussian seed source” light signal, the PFLs (pulsed fiber lasers) using such a fiber gave more energy, better beam quality, and lower ASE (amplified stimulated emission) than otherwise-similar fibers with refractive index cross-sections closer to a step index. The improvement was apparent with an excitation condition in which the input beam was close to that of a fundamental Gaussian mode despite a fiber-mode profile for the fundamental mode which was donut like.
It is believed that the possible reasons for the improvement include one or more of the following.
The present invention includes deliberately introducing the central dip such that some or all of the above are improved.
In some embodiments, such a fiber having a core with the central dip in the index of refraction is doped with a stimulated-emission species. In some such embodiments, the doping (stimulated-emission concentration) profile 411 of the core substantially matches the index-of-refraction profile of the core, in order that the pumped stimulated-emission species is more fully depleted by the primary mode (the active species is located where the light is). In some embodiments, the core is of a large diameter—a diameter so large that it would be a multimode fiber if the core had a step index-of-refraction profile, and the core supports a large mode area (LMA) optical signal. However, because of the central dip, the core supports a single LP02 mode and essentially becomes a single-mode LMA fiber. In other embodiments, the doping (stimulated-emission concentration) profile 412 of the core is substantially a step-profile.
In some embodiments, such a fiber having a core with the central dip index profile is not doped with a stimulated-emission species (i.e., the graph of the doping concentration is zero or substantially zero across the entire fiber), but such a fiber is spliced to another fiber or slab waveguide that has a core doped with a stimulated-emission species, in order that the fiber having a core with the central dip transforms an optical signal to have a mode profile that better matches the desired signal input to the core doped with a stimulated-emission species.
In some embodiments, the undoped fiber 520 (see
In other embodiments, the undoped fiber 520 having a core with the central dip index-of-refraction profile (e.g., 110) is optically coupled to a fiber or slab having the active-species doping with a central-dip index-of-refraction profile such as 110 and a step-doping profile such as 412.
In still other embodiments, the undoped fiber 520 having a core with the central dip index-of-refraction profile (e.g., 110) is optically coupled to a fiber or slab having the active-species doping with a step index-of-refraction profile (not separately shown, but similar in shape to step-doping profile 412) and a step-doping profile such as 412.
In some embodiments, a simple LMA (large mode-area) fiber (e.g., with a mode field diameter of about 20 microns or more) could be used, wherein the core primarily supports three modes: the LP01, LP11 and LP02 linear-polarization modes. The mode profiles are shown schematically in
In some embodiments, the adding of the higher-index ring 625 means that the structure 620 may now support additional higher-order modes but, in some embodiments, these modes have a higher overlap with the ring (which, in some embodiments, includes absorbing dopant) than the LP02 mode and therefore also experience less gain or more loss than the LP02 mode.
The structure shown in
In some embodiments, the present invention provides a multimode optical fiber with a transverse variance in refractive-index profile such that a particular mode (“the amplified mode”) experiences a certain gain under optical pumping, while all other modes experience either loss or a gain (g0) of less than about ninety percent (90%) of the gain of the amplified mode. Note that because fiber amplifiers operate at such high gain values, the total gain of an amplifier G=exp (g0 1) can be very high, and so small changes in g0 can make very large differences. It therefore does not take much difference in gain to strongly discriminate between modes.
In some embodiments, the present invention provides a fiber amplifier (in some embodiments, this is a pulsed optical amplifier, while in other embodiments, it is a CW (continuous-wave) amplifier), in which a multimode-type doped core contains a central dip or one or more trenches in the refractive index profile.
In some embodiments, the fiber amplifier includes a co-doping of erbium and ytterbium (an ErYb co-doped fiber).
In some embodiments of the fiber amplifier, the amplifying medium includes doping of one or more species selected from the group consisting of Er, Yb, Tm, Nd, Ho, Pr, and Sm. In other embodiments, one or more others of the rare-earth elements are used as appropriate to the wavelengths that are desired.
In some embodiments of the fiber amplifier, an input signal is launched substantially into at least two modes of the multimode-core structure. In some embodiments, the two modes are as defined by the index-of-refraction profile rather than by gain or loss dopant species.
In some embodiments of the fiber amplifier, the fiber is excited by a Gaussian beam. In some such embodiments, the Gaussian input beam substantially excites two or more modes of said multimode fiber. In some embodiments, the substantially excited modes are the LP01 and LP02 modes. In some embodiments, the LP01 mode has significantly more gain than the LP02 mode. In some embodiments, the LP01 mode has negligible field amplitude on the fiber axis. In some such embodiments, an absorbing material is doped along the fiber axis so as to provide differential attenuation to the LP02 mode. In some embodiments, the absorbing dopant is thulium.
In some embodiments, the doping of rare-earth gain species is negligible on the fiber axis and maximum at the peak of the ring index-of-refraction profile.
In some embodiments, the spotsize of the Gaussian beam is configured to provide maximum excitation of the LP01 mode.
In some embodiments, an index pedestal in the inner cladding surrounding the core is provided, improving the beam quality parameter M2 of the LP01 mode by reducing its central intensity minimum.
In some embodiments the raised index of the pedestal and the central index dip together result in a core structure which is a mathematically single-mode.
In some embodiments of the fiber amplifier, the LP02 mode has significantly more gain than the LP01 mode.
In some embodiments of the fiber amplifier, one or more active rare earth species are doped in the region of the profile corresponding to the dip in index of refraction.
In some embodiments of the fiber amplifier, an absorbing species is doped into the ring structure (i.e., the ring structure being the annular region of higher index of refraction in the outer portion of the core that surrounds the central core that has the major portion of the mode of interest and/or the active species used for amplification). As used herein, the term “active dopant” is the same as “stimulated-emission species,” also called a “lasing species,” and these function (alone or in combination with other materials) to absorb pump energy (typically light of a shorter wavelength) and to provide stimulated emission amplification of a signal wavelength (typically a longer wavelength). A stimulated-emission species is typically a rare-earth element used as a dopant in a transparent material such as glass. As used herein, a waveguide is any structure that confines light to propagate along its length (e.g., a core of a optical fiber that confines signal light, or an inner cladding of an optical fiber that confines pump light to propagate along the core, or a waveguide on a planar substrate), by any suitable mechanism such as increased index of refraction compared to the surrounding material, or photonic-crystal structures as are well known in the art.
In the following claims, the term “corresponding step profile” is defined as a step profile with equivalent peak index-of-refraction difference relative to an inner cladding and a diameter scaled to support the same number of modes as the fiber with the actual dip or trench profile. This is illustrated in
In the following claims, the term “equivalent step profile fiber” is defined as a fiber in which the diameter of the central-dip profile is the same as the step-index profile but the numerical aperture (and/or the amount of change of index-of-refraction) is adjusted (typically reduced) until the step-index profile provides the same number of modes as the central-dip profile. In this case, the advantage is related to the rare-earth dopants “following” the profile so that the local composition enables strong Yb—Er energy transfer. This is indicated in
In some embodiments, the present invention provides an apparatus that includes an optical device configured to operate in a band of wavelengths from about 1500 nm to about 1700 nm, wherein the device includes a multimode signal waveguide having a central dip in the refractive index profile, the central-dip signal waveguide having a characteristic diameter.
In some embodiments, the optical device includes a fiber, and the signal waveguide is a core of the fiber that includes a doping of active stimulated-emission species, and the apparatus further includes a source of optical pump radiation suitable to pump the active stimulated-emission species to an excited state.
In some embodiments, the core includes a co-doping of erbium and ytterbium (an ErYb co-doped fiber).
In some embodiments, the fiber, when excited by a Gaussian beam, preferentially excites an LP02-like mode of the core.
In some embodiments, the fiber is configured such that the LP02-like mode experiences a lower effective nonlinear index than it would in a substantially similar fiber having a corresponding step profile.
In some embodiments, the LP02-like mode experiences a higher dispersion slope than in a substantially similar fiber having a corresponding step profile.
In some embodiments, an effective area of the mode divided by the number of propagating modes is enhanced relative to a corresponding step profile.
In some embodiments, an LP02-like mode of the fiber has a stronger overlap with ions of the active stimulated-emission species located in the wings (i.e., the one or more rings of higher index of refraction in the periphery of the core) of the profile relative to the overlap of an LP01 mode in a fiber having a corresponding step profile.
In some embodiments, an LP02-like mode of the fiber experiences less backscatter losses than the LP01 mode of a corresponding step profile.
In some embodiments, an energy transfer from Yb to Er in the fiber having the central-dip core is greater than an energy transfer from Yb to Er in a fiber having a step-index-of-refraction core having an “equivalent step profile” in which the diameter of the core of the step-index-of-refraction profile has the same characteristic diameter as the central-dip core but where the numerical aperture of the step-index-of-refraction core is lowered by an amount that provides the step-index core with the same number of modes as the central-dip core.
In some embodiments, an advantage related to the rare-earth dopants “following” the index-of-refraction profile enables stronger Yb—Er energy transfer.
In some embodiments, the device includes no doping of active doping species (such as erbium or ytterbium).
In some embodiments, the present invention provides an apparatus that includes a fiber amplifier operating in a band of wavelengths from about 1532 nm to about 1620 nm, in which a multimode, doped core contains a central dip in the refractive index profile.
In some embodiments, the fiber includes a co-doping of erbium and ytterbium (an ErYb co-doped fiber).
In some embodiments, the fiber is excited by a Gaussian beam that preferentially excites an LP02-like mode of the core.
In some embodiments, the mode experiences a lower effective nonlinear index than it would in a substantially similar fiber having a corresponding step profile.
In some embodiments, the mode experiences a higher dispersion slope than a corresponding step profile.
In some embodiments, the effective area of the mode divided by the number of propagating modes is enhanced relative to a corresponding step profile.
In some embodiments, an LP02-like mode of the fiber has a stronger overlap with the ions located in the wings of the profile relative to the overlap of the LP01 mode of a corresponding step profile.
In some embodiments, an LP02-like mode of the fiber experiences less backscatter losses than the LP01 mode of a corresponding step profile.
In some embodiments, an energy transfer from Yb to Er is greater than that for a step-index fiber having an “equivalent step profile” wherein the profile with a dip is compared to an “equivalent step profile fiber” in which the diameter of the profile is maintained, but the numerical aperture is reduced until the profile of the “equivalent step profile fiber” provides an equal number of modes as the actual profile, such that the advantage related to the rare-earth dopants “following” the profile so that the local composition enables strong Yb—Er energy transfer.
In some embodiments, the fiber includes substantially no doping of active doping species (such as erbium or ytterbium).
In some embodiments, the fiber includes Er doping, which produces lasing and/or amplifying in the 1500 nm range (e.g., about 1500 nm to about 1700 nm). In other embodiments, the invention uses fibers doped solely with Yb, thus lasing and/or amplifying in the 1.0 micron range (e.g., about 1020 nm to about 1100 nm), when those wavelengths are also of interest.
It is to be understood that the above description is intended to be illustrative, and not restrictive. Although numerous characteristics and advantages of various embodiments as described herein have been set forth in the foregoing description, together with details of the structure and function of various embodiments, many other embodiments and changes to details will be apparent to those of skill in the art upon reviewing the above description. The scope of the invention should be, therefore, determined with reference to the appended claims, along with the full scope of equivalents to which such claims are entitled. In the appended claims, the terms “including” and “in which” are used as the plain-English equivalents of the respective terms “comprising” and “wherein,” respectively. Moreover, the terms “first,” “second,” and “third,” etc., are used merely as labels, and are not intended to impose numerical requirements on their objects.
|Cited Patent||Filing date||Publication date||Applicant||Title|
|US4009014||Sep 3, 1975||Feb 22, 1977||International Standard Electric Corporation||Optical fiber manufacture|
|US4372648||Oct 29, 1980||Feb 8, 1983||International Standard Electric Corporation||Optical fibres|
|US4447124||Oct 27, 1981||May 8, 1984||Bell Telephone Laboratories, Incorporated||Multimode optical fiber with radially varying attenuation center density|
|US4723828||Nov 9, 1984||Feb 9, 1988||Northern Telecom Limited||Bandwidth enhancement of multimode optical transmisson lines|
|US5121460||Jan 31, 1991||Jun 9, 1992||The Charles Stark Draper Lab., Inc.||High-power mode-selective optical fiber laser|
|US5261016||Dec 22, 1992||Nov 9, 1993||At&T Bell Laboratories||Chromatic dispersion compensated optical fiber communication system|
|US5361319||Feb 4, 1992||Nov 1, 1994||Corning Incorporated||Dispersion compensating devices and systems|
|US5790735||Apr 30, 1997||Aug 4, 1998||Sdl, Inc.||Optical fibre for improved power coupling|
|US5818630||Jun 25, 1997||Oct 6, 1998||Imra America, Inc.||Single-mode amplifiers and compressors based on multi-mode fibers|
|US5828802||Feb 19, 1997||Oct 27, 1998||Lucent Technologies, Inc.||Self-tuning optical waveguide filter|
|US5926600||May 22, 1997||Jul 20, 1999||Litton Systems, Inc.||Optical fiber for reducing optical signal reflections|
|US6327403||Dec 17, 1999||Dec 4, 2001||Lasercomm Inc.||Reducing mode interference in transmission of LP02 Mode in optical fibers|
|US6434311||Jan 12, 2000||Aug 13, 2002||Lasercomm Inc.||Reducing mode interference in transmission of a high order mode in optical fibers|
|US6463201||Nov 5, 2001||Oct 8, 2002||The Furukawa Electric Co., Ltd.||Light amplification optical fiber and light amplifier using the same|
|US6496301||Mar 10, 2000||Dec 17, 2002||The United States Of America As Represented By The Secretary Of The Navy||Helical fiber amplifier|
|US6574406||Sep 11, 2001||Jun 3, 2003||Corning Incorporated||Selectively absorbing optical fibers for optical amplifiers|
|US6603791||Dec 12, 2000||Aug 5, 2003||Keopsys, Inc.||High power fiber amplifiers with passive pump module alignment|
|US6614975 *||Jan 3, 2001||Sep 2, 2003||University Of Southampton||Optical fiber and optical fiber device|
|US6625354||Dec 19, 2000||Sep 23, 2003||The Boeing Company||Fiber amplifier having a prism for efficient coupling of pump energy|
|US6640031||Jun 12, 2002||Oct 28, 2003||Corning Incorporated||Dispersion compensating module and mode converter, coupler and dispersion compensating optical waveguide therein|
|US6711918||Feb 6, 2001||Mar 30, 2004||Sandia National Laboratories||Method of bundling rods so as to form an optical fiber preform|
|US6731837||Dec 14, 2001||May 4, 2004||Keopsys, Inc.||Optical fiber amplifiers and lasers and optical pumping devices therefor and methods of fabricating same|
|US6771414||Feb 1, 2002||Aug 3, 2004||Nippon Telegraph And Telephone Corporation||Optical fiber amplifier and optical communication system using the same|
|US6778782||Sep 27, 2000||Aug 17, 2004||Nortel Networks Limited||Dispersion compensation|
|US6825974||Nov 6, 2001||Nov 30, 2004||Sandia National Laboratories||Linearly polarized fiber amplifier|
|US6836607||Mar 14, 2001||Dec 28, 2004||Corning Incorporated||Cladding-pumped 3-level fiber laser/amplifier|
|US6959022||Dec 11, 2003||Oct 25, 2005||Ceramoptec Gmbh||Multi-clad optical fiber lasers and their manufacture|
|US6985660||Dec 10, 2003||Jan 10, 2006||Sumitomo Electric Industries, Ltd.||Multiple cladding optical fiber|
|US20030002834||Feb 5, 2002||Jan 2, 2003||Brown Thomas G.||Low loss isotopic optical waveguides|
|1||Adams, M. J., et al., Wavelength-Dispersive Properties of Glasses for Optical Fibres: the Germania Enigma, Electronic Letters, Oct. 26, 1978, two pages reprinted from pp. 703-705, vol. 14, No. 22.|
|2||Davis, Christopher C. , Lasers and Electro-optics Fundamentals and Engineering, Chapter 17, pp. 387-437, 1996, Publisher: Cambridge University Press.|
|3||Gloge, D., et al., GaAs Twin-Laser Setup to Measure Mode and Material Dispersion in Optical Fibers, Applied Optics, Feb. 1974, pp. 261-263, vol. 13, No. 2.|
|4||Lushnikov, P.M., Dispersion-Managed Soliton in Optical Fibers with Zero Average Dispersion, Optics Letters, Aug. 15, 2000, pp. 1144-1146, vol. 25, No. 16.|
|5||Luther-Davies B., et al., Evaluation of Material Dispersion in Low Loss Phosphosilicate Core Optical Fibres, Optics Communications, Jan. 1975, pp. 84-88, vol. 13, No. 1.|
|6||Minelly, J.D., et al., Efficient Cladding Pumping of an Er3+ Fibre, Proc. 21st Eur. Conf. on Opt. Comm, ECOC 1995, (four pages).|
|7||Payne, D. N., et al., Zero Material Dispersion in Optical Fibres, Electronics Letters, Apr. 17, 1975, vol. 11, No. 8 (two pages).|
|8||Peddanarappagari, K. V., et al., Design of Fiber Amplifier Based Communications Systems Using a Volterra Series Approach, Proceedings of the 10th Annual Meeting of the IEEE Lasers and Electro-Optics Society (LEOS), Nov. 1997, pp. 228-229, vol. 1.|
|9||Peddanarappagari, K. V., et al., Study of Fiber Nonlinearities in Communication Systems Using a Volterra Series Transfer Function Approach, Proceedings of the 31st Annual Conference on Information Sciences and Systems (CISS), Mar. 1997 (six pages).|
|10||Wang, Zi Hua, et al., Analysis of the Absorption Efficiency of Graded-Index Double-Clad Fiber, Proceedings of SPIE, 2005, pp. 821-829, vol. 5623.|
|Citing Patent||Filing date||Publication date||Applicant||Title|
|US7778498 *||Aug 17, 2010||Ofs Fitel Llc||Systems and techniques for generating cylindrical vector beams|
|US7876495||Jul 31, 2008||Jan 25, 2011||Lockheed Martin Corporation||Apparatus and method for compensating for and using mode-profile distortions caused by bending optical fibers|
|US7924500||Apr 12, 2011||Lockheed Martin Corporation||Micro-structured fiber profiles for mitigation of bend-loss and/or mode distortion in LMA fiber amplifiers, including dual-core embodiments|
|US8068705||Nov 29, 2011||Gapontsev Valentin P||Single-mode high-power fiber laser system|
|US8081667||Dec 20, 2011||Gapontsev Valentin P||Single-mode high power multimode fiber laser system|
|US8089689||Jun 23, 2010||Jan 3, 2012||Lockheed Martin Corporation||Apparatus and method for optical gain fiber having segments of differing core sizes|
|US8199399||Jun 12, 2012||Lockheed Martin Corporation||Optical gain fiber having segments of differing core sizes and associated method|
|US8218928||Apr 23, 2009||Jul 10, 2012||Ofs Fitel, Llc||Spatial filtering of higher order modes in multimode fibers|
|US8345348||Jan 1, 2013||Lockheed Martin Corporation||Method and optical gain fiber having segments of differing core sizes|
|US8705166||Dec 27, 2012||Apr 22, 2014||Lockheed Martin Corporation||Optical gain fiber having tapered segments of differing core sizes and associated method|
|US8755660||Jan 25, 2011||Jun 17, 2014||Lockheed Martin Corporation||Method and apparatus for compensating for and using mode-profile distortions caused by bending optical fibers|
|US8909017||May 30, 2012||Dec 9, 2014||Ofs Fitel, Llc||Spatial filtering of higher order modes in multimode fibers|
|US8948559 *||Mar 15, 2013||Feb 3, 2015||Ofs Fitel, Llc||Multiple LP mode fiber designs for mode division multiplexing|
|US9110352 *||Jul 3, 2013||Aug 18, 2015||The Regents Of The University Of California||Systems and methods for fiber optic parametric amplification and nonlinear optical fiber for use therein|
|US9140873||Jun 17, 2014||Sep 22, 2015||Lockheed Martin Corporation||System and method for compensating for distortions in optical fibers|
|US9207396 *||Jul 3, 2013||Dec 8, 2015||Yangtze Optical Fibre And Cable Joint Stock Limited Company||Single mode optical fiber with large effective area|
|US20090202191 *||Feb 9, 2009||Aug 13, 2009||Furukawa Electric North America, Inc.||Systems and Techniques for Generating Cylindrical Vector Beams|
|US20100271689 *||Oct 28, 2010||Ofs Fitel, Llc||Spatial filtering of higher order modes in multimode fibers|
|US20110064095 *||Mar 17, 2011||Ipg Photonics Corporation||Single Mode High Power Fiber Laser System|
|US20110064097 *||Mar 17, 2011||Ipg Photonics Corporation||Single-mode high power multimode fiber laser system|
|US20130314767 *||Jul 3, 2013||Nov 28, 2013||The Regents Of The University Of California||Systems and methods for fiber optic parametric amplification and nonlinear optical fiber for use therein|
|US20140064686 *||Mar 15, 2013||Mar 6, 2014||Ofs Fitel, Llc||Multiple lp mode fiber designs for mode division multiplexing|
|EP2478398A4 *||Sep 8, 2010||Feb 17, 2016||Ipg Photonics Corp||Multimode fiber|
|WO2011031704A2||Sep 8, 2010||Mar 17, 2011||Ipg Photonics Corporation||Multimode fiber|
|U.S. Classification||385/124, 359/342, 385/142, 385/127, 359/341.5, 385/141, 385/123, 359/341.3, 385/128, 385/126, 359/341.1, 359/343, 359/344|
|International Classification||H04B10/12, G02B6/02, H01S3/00|
|Cooperative Classification||G02B6/03605, G02B6/03661, G02B6/03633, G02B6/02023, G02B6/03611, G02B6/03688, H01S3/06729, G02B6/03694, G02B6/03638|
|European Classification||G02B6/036H2, G02B6/036H, G02B6/036L3, G02B6/036U, G02B6/036L2N|
|Nov 14, 2006||AS||Assignment|
Owner name: ACULIGHT CORPORATION, WASHINGTON
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Effective date: 20061103
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Owner name: LOCKHEED MARTIN CORPORATION, MARYLAND
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